CN-121977465-A - Performance verification method and system for optical fiber strain sensor for monitoring highway infrastructure

CN121977465ACN 121977465 ACN121977465 ACN 121977465ACN-121977465-A

Abstract

The invention belongs to the technical field of civil engineering monitoring, and discloses a performance verification method and a system of an optical fiber strain sensor for monitoring highway infrastructure, wherein the method comprises the steps of analyzing the influence rule of the parameter change of a coupling layer on the strain transfer efficiency of a sensor to be tested based on a layered material coupling mechanical model; based on a three-dimensional entity numerical model, analyzing the influence rule of the distribution process parameters of the tested sensor on the strain transmissibility, verifying the performance of the sensor in a laboratory environment by utilizing a reduced scale model, and verifying the performance of the sensor on an actual structure by monitoring data on a real highway infrastructure or a built full scale model. The invention realizes multi-dimensional and progressive performance verification of the performance of the optical fiber strain sensor for monitoring the highway infrastructure by constructing a complete performance verification system from a theoretical model to numerical simulation and then to a reduced scale model test and entity structure verification.

Inventors

LI PENGFEI
MAO YAN
LI ZHENCHUAN
HAN XU
YU JINTIAN
Wei Sicong

Assignees

交通运输部公路科学研究所

Dates

Publication Date: 20260505
Application Date: 20260122

Claims (10)

1. The method for verifying the performance of the optical fiber strain sensor for monitoring the highway infrastructure is characterized by comprising the following steps of: S1, theoretical analysis, namely, establishing a layered coupling mechanical model between an optical fiber strain sensor and a monitored structural substrate based on a shearing theory and an elastic mechanical principle, deducing an analysis expression of strain transfer coefficients of the optical fiber strain sensor, and analyzing an influence rule of coupling layer parameters of the measured sensor on strain transfer efficiency; s2, simulation analysis, namely constructing a three-dimensional entity numerical model of a matrix coupling system of the optical fiber strain sensor and the structure to be tested by adopting finite element analysis software based on a layered coupling mechanical model, and carrying out strain transmission numerical simulation under the action of load by setting a material constitutive relation and boundary conditions to analyze the change rule of the strain transmission efficiency of the sensor to be tested; S3, model test verification, namely, using a reduced scale model with a similar relation with an actual structure, installing the tested sensor analyzed in the steps S1 to S2 at a designated position of the reduced scale model according to an actual layout process of the optical fiber strain sensor, carrying out a loading test of simulating service load in a laboratory environment, and monitoring dynamic deviation between strain test data and actual strain in real time to obtain a degradation rule of linearity index and repeatability index of the tested sensor; S4, verifying the entity structure, namely arranging the tested sensor analyzed and verified in the steps S1 to S3 on a real highway infrastructure or a built full-scale model, applying actual traffic load or equivalent excitation, and monitoring and collecting performance degradation rule data of the tested sensor.
2. The method for verifying performance of an optical fiber strain sensor for monitoring highway infrastructure according to claim 1, wherein in step S1, a layered coupling mechanical model is respectively established for typical layout of two optical fiber sensors, i.e., surface-mounted type and embedded type, and a strain transfer coefficient analysis expression is used for calculating average strain transfer efficiency from a monitored structural substrate to a sensor to be tested.
3. The method of verifying performance of a fiber optic strain sensor for highway infrastructure monitoring of claim 1, wherein step S1 further comprises: Substituting a set minimum strain transfer efficiency threshold value into a strain transfer coefficient analysis expression to carry out inverse solution according to the requirement of highway engineering long-term health monitoring on the strain transfer efficiency, and inverting an optimized value interval of key layout process parameters, wherein the key layout process parameters comprise bonding layer thickness, bonding length and bonding material elastic modulus; Based on the optimized value interval, sensor standardized layout process optimization measures applicable to different types of highway foundation facilities and environmental conditions are formulated.
4. The method for verifying the performance of an optical fiber strain sensor for monitoring highway infrastructure according to claim 2, wherein in the step S2, the finite element analysis software is ABAQUS, the performing of the strain transfer numerical simulation comprises parameter sensitivity analysis, specifically, in a three-dimensional entity numerical model, strain transfer efficiency of the optical fiber strain sensor under different parameter value combinations is calculated by changing one or more parameter values in a target layout process parameter, and a mapping relation between the parameter values and the transfer efficiency is established for guiding optimization of the layout process of the optical fiber strain sensor.
5. The method for verifying the performance of an optical fiber strain sensor for monitoring highway infrastructure according to claim 1, wherein in the step S3, the loading test is specifically a fatigue loading test, and the linearity index and repeatability index are obtained as follows: after fatigue loading for a certain number of times, applying graded increasing and decreasing constant-amplitude static load to the scale model, synchronously collecting an output strain value of a measured sensor and a reference strain value measured by a reference strain gauge arranged at the same measuring point after each stage of load is stable, calculating deviation data between the output strain value and the reference strain value, Obtaining a linear fitting curve of the sensor output strain value and the reference strain value by carrying out statistical analysis on the deviation data, and taking the nonlinear error of the linear fitting curve as a linearity index; the standard deviation of the deviation data of the multiple measurements at the same load level is calculated to be used for representing the repeatability index of the sensor.
6. The method for verifying the performance of the optical fiber strain sensor for monitoring the highway infrastructure according to claim 1, wherein the step S3 further comprises a comparison verification sub-step of synchronously installing and testing at least two different layout processes for the tested sensors of the same model on the same scale model to obtain and compare degradation curves of static performance indexes under different processes so as to evaluate and screen an optimal tested sensor layout scheme.
7. The method for verifying performance of an optical fiber strain sensor for highway infrastructure monitoring according to claim 1, wherein in step S4, the performance degradation rule data includes a strain transfer efficiency decay curve, a temperature drift coefficient variation trend, and an environmental durability index monitored for a long period of time; the application of the actual traffic load adopts a mode of combining on-site vehicle loading with portable excitation equipment; The equivalent excitation is realized by a dynamic load device for simulating a vehicle axle load spectrum, and a strain response time-course curve of the section of the structure where the sensor is positioned is synchronously acquired in the load application process, so as to establish a dynamic correlation model of load and strain transfer characteristics.
8. A fiber optic strain sensor performance verification system for highway infrastructure monitoring for implementing the method of any of claims 1 to 7, comprising: The theoretical analysis module is used for executing a theoretical analysis step and internally provided with a strain transfer efficiency calculation unit and a parameter influence analysis unit which are constructed based on a shear hysteresis theory; the simulation analysis module is used for executing simulation analysis steps and comprises a three-dimensional modeling unit, a material attribute definition unit, a grid dividing and solving unit and a result post-processing unit; The model test verification module is used for executing a model test verification step and comprises a test piece preparation unit, a loading control unit, a multi-source data synchronous acquisition unit and a performance index calculation unit; the entity verification module is used for executing the entity structure verification step and comprises a site load simulation unit, a long-term monitoring data acquisition unit and a data management and analysis unit; The theoretical analysis module, the simulation analysis module, the model test verification module and the entity verification module are sequentially connected, and the output of the entity verification module can be fed back to the theoretical analysis module and/or the simulation analysis module to form a loop verification and optimization flow.
9. The fiber optic strain sensor performance verification system for highway infrastructure monitoring of claim 8, further comprising an intelligent verification and layout optimization module comprising: The data gathering unit is used for gathering and storing four-level verification data, wherein the four-level verification data are all data sets generated by theoretical analysis in the step S1, simulation analysis in the step S2, model test verification in the step S3 and entity structure verification in the step S4; the performance prediction unit is connected to the data aggregation unit, and based on the four-level verification data, a long-term performance degradation prediction model and a strain transfer efficiency correction model of the sensor are constructed by adopting a machine learning algorithm, wherein the machine learning algorithm comprises, but is not limited to, random forest regression, a support vector machine or a long-term memory network (LSTM); The intelligent decision unit is connected to the performance prediction unit and is used for receiving sensor layout parameters and environmental load information of a target project, calling a model of the performance prediction unit to perform performance simulation, and generating a layout process optimization scheme and a reliability evaluation report based on a prediction result; The feedback learning unit is connected with the intelligent decision unit and the data aggregation unit and is used for comparing actual engineering monitoring data with a prediction result and automatically triggering updating and optimizing the model in the performance prediction unit according to the deviation.
10. The system according to claim 9, wherein the multi-objective optimization process executed by the intelligent decision unit takes the full life cycle monitoring reliability as a primary objective, searches and generates a pareto optimal layout process scheme set in a process parameter space defined by verification data of the data aggregation unit, provides a corresponding prediction performance package and verification data basis for each scheme, and generates a key performance index comparison matrix of each layout process scheme by using NSGA-II or a multi-objective particle swarm algorithm, wherein the key performance index comparison matrix comprises monitoring reliability, layout cost and maintenance difficulty.

Description

Performance verification method and system for optical fiber strain sensor for monitoring highway infrastructure Technical Field The invention relates to the technical field of civil engineering monitoring, in particular to a performance verification method and system of an optical fiber strain sensor for monitoring highway infrastructure. Background In long-term service of highway infrastructure, structural safety and durability are affected by environmental and traffic load, and high-precision sensing technology is required to monitor strain of key parts in real time. The optical fiber strain sensor becomes a core sensing element due to the advantages of anti-interference, corrosion resistance and the like, but the distribution process deviation, poor interface coupling and multi-field coupling in the real environment can reduce the strain transmission efficiency, lead to signal drift or failure and influence the accuracy of monitoring data. The existing sensor performance verification method is mainly focused on factory detection and calibration, basic characteristics are evaluated under ideal conditions, mechanical coupling influence of a sensor and a structure is ignored, particularly, the sensing capability of the sensor installed by surface mounting, embedded type and the like depends on bonding layer parameters, construction process and external environment, the influence of the factors on strain transmission efficiency attenuation is difficult to reflect by the traditional means, and long-term performance of the site cannot be predicted. In current highway engineering health monitoring, sensor layout lacks unified standard and quality control standard, and the work progress uncertainty is big, if the tie coat is too thick or uneven, the heat matching problem under different road surface structures and the environment all influences the sensor performance, and lacks evaluation system, and novel sensor is difficult to obtain abundant engineering suitability evidence before promoting, leads to selecting blindly, lay at will, influences monitoring system reliability. Although research is performed on the basis of shear theory to build a model and develop finite element analysis, the model is high in simplification degree, the influences of layered structure characteristics and strain distribution of different layout modes are not fully considered, the correlation verification with measured data is lacking, numerical simulation is mostly limited to single working condition or static loading, long-term degradation under the cooperation of fatigue load and environmental aging is not covered, a laboratory acceleration test specimen and a target structure are lack of similarity, the result extrapolation uncertainty is large, and a systematic verification process is not used for optimizing material-level parameters to full life cycle performance prediction. Under the development of big data and artificial intelligence, intelligent decision support is in the primary stage of sensor performance verification application, and the existing system lacks multisource heterogeneous data integrated management capability, does not build a data driving model for progressive verification, is difficult to accurately predict performance evolution trend and optimize layout scheme, and lacks efficient optimization algorithm support when facing complex multi-objective constraint, and cannot provide operable process recommendation. Therefore, a comprehensive performance verification system integrating mechanism modeling, numerical simulation, grading test and intelligent analysis is required to be constructed, the influence mechanism of the distribution process parameters on the strain transfer efficiency is quantitatively disclosed, and the applicability and durability of the optical fiber strain sensor in a real service environment are comprehensively evaluated through step-by-step verification from a scale to a solid structure. Disclosure of Invention In order to solve the technical problems, the invention provides a performance verification method and a system for an optical fiber strain sensor for monitoring highway infrastructure, which are used for solving the problems that in the prior art, in the monitoring application of the highway infrastructure, the optical fiber strain sensor is low in strain transmission efficiency, drifting signals and even losing effectiveness in advance due to the arrangement process deviation, poor interface coupling and multi-field coupling environment effect, and a system for verifying the systematic performance is lacked. The invention provides a performance verification method of an optical fiber strain sensor for monitoring highway infrastructure, which comprises the following steps: S1, theoretical analysis, namely, establishing a layered coupling mechanical model between an optical fiber strain sensor and a monitored structural substrate based on a shearing theory and an elastic mecha